Force responsive switch



March 24, 1970 L." HL M ROSK EY 3,502,831

FOR-CE RESEONSIVE swmcn 2 Sheets-Sheet 1 Filed Feb. 5, 1969 y w /vmsol/l wm W cW M Mmw m WWW M NM WM 6W L B March 24, 1970 -L..H'. MRO-SKEYFORCE RESPONSIVE SWITCH 2 Sheets-Sheet 2 F iled Feb. :5,- 1969 INVENTORWHANNMMANI6AL United States Patent 3,502,831 FORCE RESPONSIVE SWITCHLeonard H. McRoskey, 420 Loring Ave., Los Angeles, Calif. 90024 FiledFeb. 3, 1969, Ser. No. 796,041 Int. Cl. H01h 35/02, 35/14 US. Cl.20061.49 8 Claims ABSTRACT OF THE DISCLOSURE A switch which responds tothe force of gravity, inertia,

vibration or other forces having a ring contact and a BACKGROUND OF THEINVENTION Switches of this type for closing or opening electricalcircuits are commonly referred to as trembler switches. In the prior artthere has been employed a cantilever mounted spring with a weight on itsouter end, the spring being of, rugged construction and being sensitiveto vibration to move this spring element or anode, this movementrendering the tube conductive. Such a vibration sensitive diode isdisclosed in the patent to Bianchi, et al., No. 2,999,179, dated Sept.5, 1961,'the object of this invention being to avoid actual contact ofthe anode and cathode and thus eliminate the disadvantages of switcheshaving elements which make actual contact.

Such devices have in the main been quite large and often too large formounting in smallconfined spaces. The switch of the present invention isadapted for use as a switching means closing an electric circuit inresponse .to a force, such as gravity, inertia, centrifugal, orvibration producing forces. Applicant is also familiarwith the UnitedStates Letters Patent No. 2,996,586 for a magnetic trembler switch whichhas a body of the order of 1 inch in length in which a rod between apair of magnets is supported by the magnets in spaced relation toannular contact members adjacent to the ends of the rods. A forceresponsive switch designed to avoid the disadvantages of the prior artand one which has proven to be extremely successful in actual practiceis disclosed in the copending application of Carley, McRoskey, andParsons for Switch, Ser. No. 679,098, filed Oct. 30, 1967.

SUMMARY OF THE INVENTION The present invention relates to a unique forceresponsive switch which is designed to avoid manufacturing difficultiesand to provide a sturdy and reliable construction.

The switch of my present invention permits the precise fixturing ofparts during the manufacturing process thereby eliminating therequirement to run every unit through an exhaustive test series as wouldbe required in the prior art. Automatic production is permissible as tothe base and envelope because they may be precisely of the sameconfiguration and tolerance with respect to all parts and the base andenvelope elements are fitted together exactly the same each time.

It is an object of the present invention to provide a force responsiveswitch in which the shell is formed of conductive material and comprisesa ring contact and in which there is a pendulous contact positionedwithin the envelope or shell, which consists of a closely woundunweighted helix which when subjected to a force of sufficient magnitudewill move into engagement with the ring contact and close an electriccircuit. These two contacts, namely the shell which provides the ringcontact and the pendulous contact, are insulated from each other.

3,502,831 Patented Mar. 24, 1970 It is a further object of the inventionto provide an arrangement in which the central electrode is heat in-BRIEF DESCRIPTION OF THE DRAWINGS Referring to the accompanying drawingswhich are for illustrative purposes only:

FIG. 1 is an enlarged longitudinal section of oneform of switch,incorporating the features of the invention;

FIG. 2 is a cross-sectional view taken on the line 22 of FIG. 1;

FIG. 3 is a cross-sectional view taken on the line 3--3 of FIG. 1;

FIG. 4 is an enlarged longitudinal sectional view of a switch showing analternative form with an enlarged base;

FIG. 5 is a longitudinal sectional view showing the manner in which theswaging of the envelope may be employed to change the diameter of thering contact;

FIG. 6 is a sectional view taken along the line 66 of FIG. 5;

FIG. 7 is a longitudinal sectional view showing an alternative method ofattaching a lead wire to the envelope;

FIG. 8 is a sectional view through a form of my invention employing adifferent design of base;

' FIG. 9 is a sectional view taken along the line 99 of FIG. 8; and

FIG. 10 is, a longitudinal sectional view taken through another form ofmy invention showing an alternative -method of closing an end of theenvelope and providing DESCRIPTION OF PREFERRED EMBODIMENTS Referringmore specifically to the drawings and particularly drawings FIGS. 1-3inclusive, my invention provides an envelope 20 which is made from anelectrically conductive material such as Kovar which is an alloycomposed of 29% nickel, 17% cobalt, .2% manganese and 53.8% iron; butcould be made from brass, alu minum or alloys thereof. The envelope 20has a cylindrical body 21 which is closed at one end by an end plate 22.In the form of the invention herein disclosed the outside diameter ofthe envelope is approximately .160 inch with a wall thickness ofapproximately .015 inch.

Opposite the closed end 22 is an open end of the envelope 20 having anend wall 23. The numeral 24 represents a base which has a cup orreceptacle 25 which is made from Kovar. The receptacle 25 has a sleeveor cylindrical wall 26 which fits into the cylindrical end of theenvelope 20 and has an end flange 27 which engages the end face 23 ofthe envelope 20. The receptacle 25 has an end wall 28 at its inner endprovided with a concentric opening 29. When the parts are assembled, theenvelope and receptable form a closed chamber 30 which is evacuated ofits air and is filled with an inert gas such as argon. The envelope andbase are secured together such as by welding at the joint 31 which isformed where the flange 27 engages the end wall 23.

The receptacle or cup 25 is filled with an insulation body 33 which maybe formed of epoxy or other plastic or glass. Extending into thereceptacle 25 and in engagement with its cylindrical wall 26 thereof isan electrode 34 to which a circuit wire may be connected in order thatthe receptacle 25 and envelope 20 are connected to one side of anelectric circuit. The insulation material when molded into place securesthe electrode 34 in place. There is also a central or concentricelectrode 36 which is made from an alloy such as Dumet which is an alloyconsisting of 54% iron, 46% nickel and copper plated. The electrode 36is approximately .016 inch in diameter, this same material having thesame diameter as employed in the electrode 34. The electrode 36 ispositioned concentric to the axis of the envelope 20 and the axis of thereceptacle 25. The electrode extends from the exterior of the switchthrough the insulation body and centrally through the opening 29 in theend wall 28, the opening 29 being larger than the electrode 36 so thatthese parts are not in electrical contact with each other.

When forming the subassembly consisting of the receptacle, the body ofinsulation and the two electrodes, these parts are held accurately inplace by a suitable jig or fixture and the insulation is then pouredinto place and when it hardens the subassembly has the parts accuratelysecured together.

Applied to the inside face of the end wall 28 is an insulation disc 38which along with the body 33 has heat insulation qualities. This is forthe purpose of preventing heat occasioned by welding of the envelope andreceptacle, from reaching the inner end of the electrode 36.

Secured to the inner end of the central electrode 36 is a movablevibration sensitive pendulous contact such as generally indicated at 40,this contact being in the form of a helix or coiled spring in which theturns are closely wound with respect to each other. For simplificationthe drawings show the turns of the spring out of contact but in actualpractice the coil is a closely wound coil. The contact is made fromtungsten wire and is approximately .003 inch in diameter and theinternal diameter of the helix is approximately .016 inch. The lower end41 of the helix is wound so that its inner diameter is substantiallythat of the electrode 36. These two parts are secured together by a weld42 which is positioned away from the end of the pendulous portion of thespring 40 in order that the heat from this spot weld will not damage ordraw the temper of the helix.

The pendulous contact 40 rests along the longitudinal axis of theenvelope 20 when the trembler switch is mounted in an upright positionas shown in FIG. 1. The sectional view FIG. 2 shows the contact 40 in acentral position. The cylindrical body 20 constitutes a ring contactwhich may be engaged by the pendulous contact 40 when it moves in anyradial direction. With the switch in this vertical position, the partsare designed so that the pendulous contact 40 will be deflected when theforce acting on the switch is two Gs plus or minus three tenths. If theswitch is placed in a horizontal position, the pendulous contact willbend downwardly so that it is closer to the lower portion of the wall ofthe cylindrical body and therefore contact will be made at a lower forcesuch as for example as one G.

The amount of force required to close the contacts may be varied bychanging the diameter of the envelope 20 or the diameter of thependulous contact 40. Also the closing force may be varied by making achange in the diameter of the wire from which the pendulous contact 40is made.

In the operation of my invention, the electrodes 34 and 36 are connectedin an electric circuit which electric circuit is connected to any deviceWhich is to be actuated. Whenever forces reach a predetermined amount,contact 40 will engage the ring contact or envelope 20 closing thecircuit and causing an operation.

In the form of the invention shown in FIG. 4, the diameter of theenvelope 20 is .160 inch. In this arrangement the end portion or base 50is in the form of an enlargement or bell having a bottom wall which isengaged by the wall 28 of the receptacle 25.

In FIGS. 5 and 6 there is shown an alternative construction forobtaining the diameter of the ring contact. In this form of my inventionthe cylindrical wall 21 of the envelope 20 is swaged as indicated at 60to form an annular contact ring 61 which is of a diameter of .160 inch.This swage '60 may be of different depths depending upon the desireddistance which is required between the ring contact 61 and the pendulouscontact 40.

FIG. 7 shows the form of the invention in which the electrode 34 isremoved and in its place is an electrode 70 secured to the top end ofthe envelope 20. In this arrangement, the wires of the circuit areconnected to opposite ends of the switch.

In FIG. 8 the base is in the form of a metal body which may be made ofKovar metal and which is separated from the envelope by means of aninsulation sleeve 82 having a flange 84 positioned between a flange ofthe body 80 and the end wall 23 of the envelope. The electrode 36 may beformed integral with the body 80 as indicated at 36a and there may be aninner electrode 36b which is formed concentric to the longitudinal axisand which supports the pendulous contact 40'.

In FIG. 10 the enevlope 20 is in the form .of a tube and does not havean integral end 22. The upper end of the envelope sleeve is closed by aKovar plug which has an electrode 102 connected to it. In this form ofmy invention, the electrodes 36a and 102 are in alignmentwith each otherat the opposite ends of the switch.

I claim:

1. A force responsive switch comprising:

(a) a conductive envelope having an annular portion providing a contact;

(b) a flexible pendulous contact formed of a tightly wound helixextending longitudinally with respect to said envelope and having aportion within the annular portion of said envelope, soid pendulouscontact being adapted to be moved by a predetermined force so as toengage said annular portion;

(c) a base closing one end of said envelope and including insulationmeans; I

(d) an electrode insulated from said envelope by said insulation meansand connected to said base; said electrode supporting said pendulouscontact at one of its ends'and extending to the exterior of saidenvelope; and

(e) means whereby said pendulous contact completes an electric circuitonly upon engagement of the helix portion with said annular portion.

2. A switch as defined in claim 1 in which said envelope has acylindrical end and in which said base includesa cylindrical shell whichfits in said cylindrical end anda body of insulation material positionedwithin said cylindrical shell for supporting said electrode concentricwith said envelope and out of electrical contact with said shell andsaid envelope.

3. A switch as defined in claim 1 in which said conductive envelope iscylindrical and has an area of reduced diameter which forms a ringcontact and in which the pendulous contact extends through said reducedarea.

4. A switch as defined in claim 1 in which said base includes a body ofconductive material positioned in the end of said envelope andsupporting said electrode, said insulation means comprising aninsulation wall between said base body and said envelope to maintainthese parts out of electrical contact.

5. A switch as defined in claim 4 in which there is; a metal plug in theopposite end of said envelope to said base, said metal plug having anelectrode: connected thereto on the exterior of said envelope. H

6. A switch as defined in claim 2 in which said envelope is cylindricaland is provided with an enlarged cylindrical end an in which said baseincludes a metal cup having a cylindrical wall fitting in said enlargedcylindrical, end and in which said metal cup has an end wall with anopening in it through which said electrode extends, said body ofinsulation supporting said electrode in an axial 5 6 position and out ofelectrical contact with any metal part References Cited of said cup orsaid envelope.

7. A switch as defined in claim 6 in which there is a UNITED STATESPATENTS heat insulation element applied to the inner face of the2,407,073 9/1946 GOTFOH 200-6151 end wall of Said metal cup 2,983,8005/1961 Rablnow 2006l.45 8. A switch as defined in claim 6 in which thereis a 5 3,415,960 12/1968 Koumeyer second electrode extending into saidcup in contact with the cylindrical wall thereof and held in place bysaid ROBERT SCHAEFER Pnmary Exammer insulation material. M. GINSBURG,Assistant Examiner

